Agricultural planting machines are manufactured in different forms, one of which is a device commonly referred to as an air seeder. The air seeder carries seed, fertilizer and possibly other chemicals in a tank that opens into a pneumatic conveyance mechanism that transports the seed and perhaps fertilizer to a planting apparatus, one of which can be commonly referred to as a disc opener.
Disc openers are designed to move through the soil and place product such as seed, fertilizer, or other micronutrients into the ground while creating as little disturbance as possible to the surrounding environment. To accomplish this goal, the disc usually opens a small trench or furrow into the ground in which the product is place. A pneumatic conveyance mechanism then conveys the product from the central tank to the small trench.
As shown in FIG. 6, the disc 22 typically contains a dust cap 21 to prevent dust, dirt, and other contaminants from entering into the bearings (not shown). However, if the dust cap 21 is not held on by a retaining strap (not shown), the dust cap 21 may be easily knocked off the disc 22 by debris in the field, thereby permitting dirt and other debris to enter into and clog the bearings located in the hub 26. Moreover, the dust cap 22 is easily damaged in the field or when it is removed to access the hub 26 for service, and often needs to be replaced.
In addition, the dust cap 22 can limit the range of motion of a gauge wheel 24 due to the interference between the dust cap 21 and the inside of the gauge wheel rim. As can be seem in FIG. 2, the gauge wheel 24 has an axis of rotation A (indicated in FIGS. 3 and 5) that is located in close proximity to the axis of rotation of the disc 22, which undesirably permits soil to build up on the disc 22.
Accordingly, it is desirable to provide a disc opener that overcomes the disadvantages of the known prior art disc openers.